Research Of Establishing Phthalocyanine-Based Interphase On The Interfacial Properties Of Carbon Fiber Composites

The interfacial problem of carbon fiber composite was always been key constraint to curb its application in structural materials and functional materials.With the development of technology and the process of researching on the interfacial science,it is not only necessary to improve the bonding strength of the interface,but also to ensure that the interphase can meet the needs of current applications,and promote the development of carbon fiber composite materials in the direction of structural and functional integration.In this paper,through the structural design of the interphase,the problem of poor temperature resistance of the interphase was solved,the importance of the interaction between the two interfaces was discussed,and the functional application of the carbon fiber composite material was developedA novel interphase with phthalocyanine-based cross-linking point was designed.The high-temperature interfacial performance of carbon fiber composites was improved by increasing the cross-linking density and glass transition temperature(T_g)of the interphase.The high-heat-resistant interphase was tailored by tetraamino-phthalocyanine(TAPc)with abundant amine groups and rigid heteroaromatic structures coated on the surface of the carbon fibers.Compared with commercial carbon fiber(CF-commercial),the interfacial shear strength(IFSS)of TAPc-coated carbon fiber(CF-TAPc)increased by 127.3%at 150 ?.Atomic force microscopy(AFM)results indicated that the modulus of the CF-TAPc interphase was much higher than that of CF-commercial at 180?.Combined with the thermomechanical properties of different bundled composite,and using the Arrhenius formula to calculate the activation energy required for the glass transition of the interphase of different composite,it was proved that the CF-TAPc interphase possesed a higher thermomechanical stability.The results showed that the multi-amino reaction sites and the rigid structure of TAPc increased the T_g of the interphase,thereby improving the high-temperature interfacial performance of carbon fiber composites.Using solvent evaporation induced self-assembly method and the temperature-responsiveness of the phthalocyanine assembly structure,"doughnuts","nanowires","nanobelts" and "diamonds"-shaped assembly morphologies were grown on the surface of the carbon fibers.The effects of assembly time,temperature and nucleation site on the morphology of TAPc assembly were studied,and it was shown that temperature was a key factor affecting the morphology of the assembly.X-ray diffraction(XRD)was used to study the effect of temperature on the assembled crystal form of TAPc,which showed that the crystal form remained consistent in the temperature range of 120-200?.The relationship between the different assembly morphologies of the carbon fiber surface and IFSS was explored,which showed that the surface growth of "nanobelts" composites had the best interfacial performance,and the mechanism of the influence of surface morphology on the interfacial performance was discussed.Six kinds of carbon fibers with different surface chemistry were prepared by acid oxidation method,and the relationship between surface chemistry and interfacial adhesion and interfacial performance was studied.The contents of different chemical functional groups on the surface of carbon fibers were counted by X-ray photoelectron spectroscopy,and the tensile strength and weibull distribution of monofilament carbon fibers were characterized.The adhesion of TAPc molecules to different carbon fiber surfaces was quantitatively tested by AFM tip functionalization.Through the control of the conditions,six types of carbon fibers with TAPc "nanobelts" grown on the surface and consistent in surface morphology and surface wettability were obtained.The relationship between the IFSS and the adhesion forces of carbon fiber composites was studied,and the correlation between the types of chemical functional groups on the surface and IFSS was analyzed.Providing an effective surface modification guide program for the purpose of increasing the IFSS.A hierarchical nanostructure of TAPc nanowires@graphene oxide(CF-TAPc NWs@GO)was prepared on the surface of carbon fibers by one-step solvent evaporation induced self-assembly method.XRD and ultraviolet-visible spectroscopy indicate the assembly mechanism of TAPc nanowires,which is the ?-phase TAPc crystal form obtained by J-type aggregation.After the modification of the AFM tip,the adhesion between different carbon fibers and TAPc molecules was quantitatively characterized,explaining the selective growth of TAPc nanowires.The dynamic adsorption of resin on different carbon fibers reflects the wettability of the fiber surface.Compared with untreated carbon fiber,the IFSS of CF-TAPc NWs@GO composites increased by 66.9%and 206.6%at 30? and 180?,respectively.AFM modulus test shows that TAPc NWs@GO hierarchical nanostructures form a modulus transition layer at the interphase,which plays a role in transferring stress,and causes interfacial failure to occur in the form of energy-consuming cohesive failure.In addition,the multi-layer structure of TAPc NWs@GO brings rich interfacial polarization centers and more conductance losses,giving carbon fiber composite excellent electromagnetic shielding performance.When the content is only 0.5 wt%,the electromagnetic shielding efficiency is 29 dB at 9.6 GHz,an increase of 108.3%compared to untreated carbon fiber.The research results show that the CF-TAPc NWs@GO composite has great potential for the application of structural and functional integration.